1. Field of Invention
The invention relates to a technical field of an external connection structure of an electric motor that is incorporated in vehicles, etc.
2. Description of Related Art
Generally, in electric motors of this type, there are some motors in which a holder stay, to hold brushes slidably in contact with a commutator of an armature shaft, is provided on an end cover that covers one end of a cylindrical yoke. An example of such an electric motor is a fan motor.
In such electric motors, in order to supply an external power source to the brushes, conductive plates that are conductive to the respective brushes extend onto the holder stay, formed of an insulating material, and external connection members are connected to the conductive plates. There are two available types for the external connection structure, one of which is of a lead-wire specification, and the other of which is of a direct coupler specification that is attached to an end cover and integral therewith. Generally, these two types are separately used, corresponding to an object or location in which the fan motor is mounted, and the place where it is installed. In this case, common uses of components become a theme in view of decreasing costs and simplifying production. For example, as shown in FIGS. 11(A) and 11(B), a lead wire 36 or a coupler 37 is connected through a notched portion formed on the outer periphery of the holder stay 35, whereby it is considered that the holder stay 35 can be commonly used.
However, a type in which a fan motor is formed with a lead-wire is, as shown in FIG. 11(A), structured so that end portions of pig tails 38a led out from the respective brushes 38 are connected to the respective connection portions 35a provided at the holder stay 35, and the corresponding end portions 36a of the lead wire 36 dragged into the holder stay 35, as an external connection member, are connected to the respective connection portions 35a. To the contrary, a type in which the fan motor is formed with a direct coupler is, as shown in FIG. 11(B), structured so that respective end portions of pig tails 38a led out from the respective brushes 38 are connected to connection portions 35b that are provided at the holder stay 35 and are differently shaped from a connection portion 35a for the above-described lead wire, an intermediate connector 39 is connected to the respective connection portions 35b, and a coupler 37 fitted into the outer surface of the holder stay 35 is connected to the corresponding intermediate connector 39. Therefore, with regard to the lead-wire type fan motor and direct coupler type fan motor, separate members are required for peripheral components of the brushes 38, that is, between the pig tails 38a and external connection members 36, 37, wherein it becomes cumbersome or troublesome to manage products, and production costs are accordingly increased. An object of the invention resides in these points.
In view of these and other problems, the invention was developed. It is therefore an object of the invention to provide an external connection structure of an electric motor structured so as to be provided with a holder stay, which holds at least a pair of brushes slidably in contact with a commutator of an armature shaft, at an end cover that covers one end of a cylindrical yoke, wherein when providing a connection receiving portion that is made conductive to the brushes and is connected to an external connection member to secure an external power source, the connection receiving portion is located between the brushes adjacent to each other in the circumferential direction, and is composed of a conductive plate that can be visually observed via a through-hole opened at the end cover, and the visually observable portion of the conductive plate has a fitting portion, into which an external connection member to be inserted through the through-hole in the axial direction is fitted, formed thereon.
With such a structure, either of a lead wire or a direct coupler can be connected to an electric motor wherein common use of the components can be achieved.
In such a type, the fitting portion according to the invention may have a ring hole, which is oriented in the axial direction, formed thereon, and the circumferential portions thereof are formed of a pair of ring-shaped portions that are resiliently deformed so as to be brought into contact with each other and to be separated from each other.
Also, in such a type, the fitting portion according to the invention may be formed to be U-shaped, in which a recess portion that can be inserted in the axial direction is formed.
Further, in such a type, in the connection receiving portion according to the invention, an external lead-out coupler may be connected thereto and incorporated therein, a projection portion that may be inserted into the through-hole is formed on the lead-out coupler, and a projection end portion of a terminal built in the projection portion may be connected to the fitting portion.
Still further, in such a type, lead wires may be connected to the connection receiving portion according to the invention, the lead wires may be inserted into the through-hole via a grommet inserted in the through-hole, and the insertion tip end portion may be pressure-fitted to the fitting portion.